1. Field of the Invention
The invention concerns a method of synchronizing the presentation of components of a dynamic nature and components of a static nature of an interactive multimedia document in a system for presentation of such documents.
It applies in particular to a system for presentation of interactive multimedia documents used in a hospital environment to construct and to use an interactive document base of surgical records or actions.
2. Description of the Prior Art
Multimedia documents utilize information of different kinds: animated video sequences, sound, text, graphic images, fixed video images, etc.
From a temporal point of view, the information can be classified into two categories:
information of a dynamic nature, the presentation of which is naturally associated with a display time; this is the case with animated video and with sound. The information is generally stored on physical media (video server, audio server, video disk, magnetic tape, etc) with a coded timebase or "time code". For example, recording animated video on a video disk implies conjointly storing an image number with each of the fixed images that constitutes it (on the base of 25 images per second in the case of European video standards); PA1 information of a static nature, the presentation of which is not fundamentally associated with a display time; this is the case with text, with graphic images and with fixed video images. This information is stored on physical media with no associated timebase. PA1 representing the document and its dynamic and static components in the interactive multimedia document presentation system using an object-oriented model to define the interactive multimedia document in the form of a root multimedia object, each component of a dynamic nature of the document in the form of a dynamic monomedia object and each component of a static nature of the document in the form of a static monomedia object, PA1 providing in the root multimedia object and in each dynamic or static monomedia object synchronization data relating to times of presentation of the document in a logical temporal frame of reference for a certain speed of presentation of the multimedia document, the logical temporal frame of reference being derived from a coded temporal frame of reference supplied by a storage medium for components of a dynamic nature of the document, PA1 providing in the root multimedia object and in each static monomedia object synchronization data relating to a time of change of speed of presentation of the document in the logical temporal frame of reference, PA1 supplying in the root multimedia object and in each static monomedia object synchronization data relating to a time of presentation of the document in a physical temporal frame of reference supplied by a clock, PA1 supplying in the root multimedia object and in each static monomedia object synchronization data relating to a time of change of speed of presentation of the document in the physical temporal frame of reference, PA1 supplying in each dynamic monomedia object synchronization data relating to times of presentation of the document in the coded temporal frame of reference, and PA1 processing the synchronization data on each change of speed of presentation of the multimedia document to coordinate the presentation of the components of a dynamic nature and the components of a static nature thereof.
In a multimedia document, information of a static nature can be presented at the same time as other information of a dynamic nature. When the multimedia document is interactive, i.e. when it is possible for the user to change the speed of presentation of the document, the problem is to be able to coordinate the presentation of these various components, especially when the user changes the speed of presentation of the multimedia document.
Under the future MHEG standard (Multimedia and Hypermedia Expert Group--ISO/IEC DIS 13522-1), a multimedia document must be represented in a system for presentation of interactive multimedia documents in accordance with an object-oriented model.
The aim of the invention is to propose a method compatible with the future MHEG standard for synchronizing presentation of components of a dynamic nature and components of a static nature of interactive multimedia documents in a system for presentation of such documents in order to obtain harmonious temporal behavior of the components of a dynamic nature and of a static nature when the user interacts with the presentation system to modify the speed of presentation of the multimedia document.
Another aim of the invention is to propose a method of this kind that is simple to implement in object-oriented programming.